This
paper explores the deplorable condition of fish fauna of Pune urban area that
once revealed 25 species new to science out of total 26, described by Sykes in
1841 during his study on the fish fauna of Deccan (Ghate and Wagh, unpub.; Tilak
and Tiwari, 1976). After a silent century, there was a sudden spurt of
publications. The huge collection of fishes made by Fraser (1942) from Pune area
was investigated by Hora and Misra (1942) recording 54 fish species. Suter
(1944) added 17 species to Pune list. Tonapi and Mulherkar (1963) recorded 60
fish species from Pune, 25 being new local records. Yazdani and Mahabal (1978)
recorded 34 fish species from Indrayani river. To assess the urbanization
impact, Ghate and Wagh (unpubl.) resurveyed Mula and Mutha Rivers between 1992
and 1995, to list 64 fish species, 14 of which were fresh local records. All
this literature records 110 fish species from Pune urban area, studied by us
here. This re-survey reports about species extinction, population changes and
introductions in relation to each other and various human influences.

Methodology

Our
study area covers 25 km radius from the Pune City Post. Waterbodies here
includes Mula River, Mutha River, Mula-Mutha River, a part of Indrayani River, a
part of Pavana River, and three lakes - Katraj upper lake, Pashan lake, and
Lakaki lake. Sampling this year involved collection at randomly chosen spots at
these waterbodies and the related local markets. The specimens were preserved in
5% formalin in Abasaheb Garware college. Fishes were identified with the help of
literature (Talwar and Jhingran, 1992; Menon, 1987; Jayaram, 1991; Day, 1878).
Identification was verified with the help of Kerala Forest Research Institute (KFRI),
Peechi where we found accessible expertise. Relative abundance of each fish
species, population changes, and probable driving forces for population change
were recorded from field observations and interviewing local fishermen.

Results and
Discussion

We
presently recorded 66 species from 38 genera and 18 families, taking the records
for the area to 114 species from 47 genera and 22 families, depicted in the
annex along with ecological parameters. We could not collect 48 species recorded
earlier of which 18 fish species appear locally extinct form folk perceptions
and habitat quality. Remaining 30 species are too rare, besides possibly
escaping detection due to seasonal variations and sampling limitations. We doubt
the presence of 12 fish species recorded earlier from Pune. Population of 6
species appears declining. Seven fish species have been introduced here
recently. We recorded afresh 4 natural species from this area. The common and
widespread species include Notopterus notopterus, Salmostoma boopis, Rasbora
daniconius, Garra mullya, Mystus bleekeri, Oreochromis mossambica, Channa
marulis etc. Five species are rare while another 7 are only occasionally
encountered. About 25 species are recorded from a one or two localities each.
Aundh and Yerwada are most important localities hosting about a dozen such
localised species each.

The 18
species that have most possibly become locally are primarily large size fishes
belonging to genera such as Anguilla, Tor, Bagarius, Silonia etc. having
high consumption value and subject to heavy harvesting. Siltation due to
catchment erosion or waste dumping makes the water column shallow, depriving the
larger fishes their habitat. Human harvests affect 19 species including 6 that
have shown significant decline, given their high food value and demand.
Pollution has also driven significant population decline or loss. A locally
extinct fish Ompak pabo was recorded here by Fraser in 1942. Of late, it
has been recorded only in the far upstream of Mula River (Kharat et al,
unpubl.). The two major rivers of Pune City, Mula and Mutha, are highly polluted
owing to organic and inorganic waste. Mula River flows through an industrial
zone and hence inorganic salts and heavy metals from the industrial wastes
contaminate the water. This has probably resulted in absence of all fish species
except Oreochromis mossambica near Khadki. Organic pollution has
triggered spread of water hyacinth plants covering water surface in many places.
While Katraj upper lake is polluted mainly by domestic sewage, Pashan lake is
polluted also by industrial effluents. While this has affected most fish
negatively, populations of few species such as Heteropneustus fossilis
that can withstand organic pollution due to its breathing ability are even
increasing. The introduction of commercially important fish such as Cyprinus
carpiocommunis, Oreochromis mossambica have probably driven
such as Labeo
fimbriatus. Population decline of Aplocheilus liniatus feeding on
larvae may be attributed to resource competition with introduced exotic
larvivorus fishes of the family Poecillidae.

We
doubt, based on circumstantial evidence, earlier of records a dozen fish species
such as Notopterus chitala here. Neoissochilus wynnaadensis, a
cyprinid fish recorded by Tonapi and Mulherkar (1963) is actually species
endemic to Kerala (Shaji and Easa, 1998). Singh and Yazdani (1992) had likewise
doubted the occurrence of Osteobrama cotio cunma from Mula-Mutha River.
We report four species for the first time from the area. Cirrhinus cirrhosus,
the cavery white carp, is a common fish in the Deccan (Nagulu et. al.,
2000) and one specimen was collected from our study area. However, despite these
four new geographical records, we conclude our findings on the sad not of
decline of over third of the recorded species, another sixth having become
locally extinct. Impending fish erosion cannot be minimised without halting
siltation and promote optimal, rather than maximal harvests; and exploring
checks on growth of exotic species.